Google Voice Search
Google Voice Search is, frankly, amazing. Not because it works well. Most of my searches so far have been comically misinterpreted, though I note that (for research purposes only you understand) "Britney Spears" has a 100% success rate, even when I don't employ my appalling California accent.
No - to me, it's the sheer chutzpah of doing something like this, and the laser-like focus on reducing the time between deciding your wanting to know something, and Google giving it to you. I touched on this topic briefly in my talk on Monday at Future of Mobile, and Tim O'Reilly has a nice post about mobile being the lynchpin between humans and the cloud - spot on.
Can you imagine what sort of world we'll live in in 5 years time, when improvements in voice recognition (probably based around brute-force techniques rather than smart voice recognition algorithms - scale's just another tool to these guys) put an increasing percentage of our species' collective knowledge even closer? Beautiful.